Mapping Patterns of Nodal Metastases in Esophageal Carcinoma: Rethinking the Clinical Target Volume for Supraclavicular Nodal Irradiation

Abstract

Background: To map detail distribution of metastatic supraclavicular (SCV) lymph nodes (LN) in esophageal cancer (EC) patients and determine the precise radiation therapy clinical target volume (CTV).Methods: A total of 101 thoracic esophageal carcinoma patients after surgery experienced SCV LN metastasis were retrospectively examined. The SCV region is further divided into four subgroups. Using hand drawings registration, nodes were mapped to a template computed tomogram to provide a visual impression of nodal frequencies and anatomic distribution. Results: In all, 158 nodes were considered to be clinical metastatic in the SCV region in the 101 patients, 74 on the left and 84 on the right. Seven of 158 (4.4%) positive LN were located in group I, 78 of 158 (49.37%) were located in group II, 72 of 158 nodes (45.6%) were located in group III, 1 of 158 (0.63%) located in group IV. Conclusions: According to our results, the SCV group II and group III are considered to be the high risk regions of esophageal squamous cell carcinoma (ESCC) LN metastasis, which were defined as elective nodal irradiation (ENI) areas. was the most common site of recurrence regardless of the tumor location. Even among patients with lower thoracic ESCC, the incidence of SCV LN recurrence was as high as 33.8%. Similar to finding of Wu and colleagues, Cai et al. (6) performed a study to investigate the patterns of regional LN recurrence after radical surgery for ESCC. The results showed that SCV areas were the most common site of recurrence, followed by mediastinal and abdominal areas. As such, several studies also indicated that the incidence of SCV LN recurrence was a common site of recurrence after radical surgery (range, 33.3% to 75.0%) (7-9). The available data indicates that postoperative radiotherapy could reduce locoregional recurrence and improve overall survival of ESCC patients. Furthermore, the major of studies suggested that the SCV areas should be included in prophylactic radiotherapy for patients with upper, middle, and lower thoracic EC (6,(11)(12)(13).However, delineating the SCV region lymph nodal clinical target volume (CTVn) for esophageal carcinoma remains a challenging task. Currently, data documenting the precise location of involved SCV region LN in esophageal carcinoma are scarce. It is desirable to define detailed involvement patterns in the SCV region, so that these areas can be better covered and treated with an adequate radiation dose. Here, we describe the distribution of SCV LN metastasis for esophageal carcinoma patient after surgery according to computed tomography (CT) imaging in our institution, then analyzed the anatomic distribution of SCV region LN to outline the spatial and probabilistic distributions of LN, and to provide data for an evidence-based approach to SCV region radiation therapy field design. Thus, we could minimize inconsistency of irradiation field and to achieve precise radiotherapy of the SCV region for postoperative radiotherapy. Methods Patient populationWe retrospectively reviewed the...

Explore the radiotherapeutic clinical target volume delineation for small cell lung cancer with lower cervical lymph node metastasis according to CTimages

“…The positions of the metastatic lower cervical LNs for all enrolled patients were re-read respectively and then recorded the positions of positive LNs based on previous literature [21,22].…”